That’s awesome good luck with it .you should post a picture of it when it’s done if you can .if you’re ever looking for eggs let me know .i only breed coturnix here
Suggestion ....first of all coturnix lay year round no seasonal if you have a light fix for them . Just give more lighting and trust eggs will come I keep mine indoors and it just helps with lighting more eggs and easier clean up with the style cages I have again
I’ve never used a dimmer (though the idea seem well fitting for adjusting temps )and never had issues or chicks die off .my setup was similar .without a dimmer I would suggest a dark hut that’ll be cooler so they can adjust to their needs